1. Field of the Invention
The present invention relates to a gate valve and, more particularly, relates to a pendulum gate valve for use in a processing device for processing a semiconductor wafer or the like.
2. Description of the Prior Art
In a processing device for processing a semiconductor wafer, a liquid crystal substrate or the like, the wafer or the substrate is inserted into or taken out from one of many kinds of processing rooms through passages each having a gate valve, for example, a pendulum gate valve. It is necessary to prevent as much as possible foreign matters from entering into the processing room.
Such gate valve is described in the U.S. Pat. No. 6,089,537. In such gate valve, a valve disc is moved up and down while separating from a valve seat, and the valve disc is brought into contact with the valve seat by urging the side surface of the valve disc toward the valve seat when the valve disc is positioned to face to the valve seat.
FIG. 17 and FIG. 18 show the conventional pendulum gate valve having a hollow box-like valve housing 1 in the shape of oval in cross section, defining an interior space. The valve housing 1 includes a pair of opposing circular openings 2 and 3 through which an article to be processed and/or processing gas pass into a process chamber when the gate valve is opened.
The gate valve includes a valve disk 5. When the gate valve is closed, the valve disk 5 comes into contact with a valve seat 4 provided in the interior space around the edge of the opening 2. The valve disk 5 is held by a pivot arm 6 and moved by an arm driving device 8 centering around a pivotal point 7 formed on the valve housing 1 between a completely opened position and a completely closed position.
In the above conventional pendulum gate valve, the valve disk 5 in the completely closed position is urged toward the valve seat 4 through the tip end of the arm 6 by the arm driving device 8. Accordingly, it is necessary to use the arm driving device 8 large in power and size, and the arm 6 large in diameter.
Other conventional gate valve is disclosed in the Japanese Patent Laid-Open No. 277,876/91. In this gate valve, a valve plate is provided facing the valve disk, and a pressure fluid is introduced into a space between the valve plate and the valve disk to separate with each other, so that the valve disk is urged to the valve seat by utilizing the reaction force to the force applied to the valve plate.
In this gate valve, however, a device for introducing the pressure fluid into the space must be provided, so that the gate valve becomes large in size.
Accordingly, it is an object of this invention to provide a pendulum gate valve free from the above defects.
The invention can be summarized as follows.
A pendulum gate valve of the present invention comprises a valve housing including an interior space and first and second openings opposite to each other;
a valve seat disposed in the interior space around the edge of the first opening;
a valve disk mounted relative to the valve housing so that the valve disk is movable within the interior space between a completely opened position and a completely closed position, the valve disk being constructed so that when the valve disk is moved to the closed position the valve disk engages the valve seat and seals the first opening;
a pivot arm, the base end of which is pivotally secured to the valve housing;
an arm driving device for moving a tip end of the pivot arm between a first position where the valve disk is in the completely opened position and a second position where the valve disk is in the completely closed position; and
a power transmission device for transmitting the movement of the pivot arm to the valve disk;
the power transmission device having a first roller guide groove formed on the valve disk, a valve disk support fixed to the tip end of the pivot arm, movable relative to the valve disk, a second roller guide groove formed on the valve disk support so as to face to the first roller guide groove, a third roller guide groove formed on the valve disk support, a supporting plate, a fourth roller guide groove formed on the supporting plate so as to face to the third roller guide groove, a first roller engaging with the first and second roller guide grooves, and a second roller engaging with the third and fourth roller guide grooves, each of the first and second roller guide grooves extending downwards obliquely so as to be separated from the valve disk, and each of the third and fourth roller guide grooves extending downwards obliquely so as to approach to the valve disk.
A pendulum gate valve of the present invention comprises a valve housing including an interior space and first and second openings opposite to each other;
a valve seat disposed in the interior space around the edge of the first opening;
a valve disk mounted relative to the valve housing so that the valve disk is movable within the interior space between a completely opened position and a completely closed position, the valve disk being constructed so that when the valve disk is moved to the closed position the valve disk engages the valve seat and seals the first opening;
a pivot arm, the base end of which is pivotally secured to the valve housing;
an arm driving device for moving a tip end of the pivot arm between a first position where the valve disk is in the completely opened position and a second position where the valve disk is in the completely closed position; and
a power transmission device for transmitting the movement of the pivot arm to the valve disk;
the power transmission device having a first roller guide groove formed on the valve disk, a valve disk support fixed to the tip end of the pivot arm, movable relative to the valve disk, a second roller guide groove formed on the valve disk support so as to face to the first roller guide groove, a third roller guide groove formed on the valve disk support, a supporting plate, a fourth roller guide groove formed on the supporting plate so as to face to the third roller guide groove, a first roller engaging with the first and second roller guide grooves, and a second roller engaging with the third and fourth roller guide grooves, the first roller guide groove extending downwards obliquely so as to be separated from the valve disk and then extending downwards substantially vertically, the second roller guide groove extending upwards obliquely so as to approach to the valve disk and then extending upwards substantially vertically, the third roller guide groove extending downwards obliquely so as to approach to the valve disk and then extended downwards substantially vertically, and the fourth roller guide groove extending upwards obliquely so as to be separated from the valve disk and then extended upwards substantially vertically.
A pendulum gate valve of the present invention comprises a valve housing including an interior space and first and second openings opposite to each other;
a valve seat disposed in the interior space around the edge of the first opening;
a valve disk mounted relative to the valve housing so that the valve disk is movable within the interior space between a completely opened position and a completely closed position, the valve disk being constructed so that when the valve disk is moved to the closed position the valve disk engages the valve seat and seals the first opening;
a pivot arm, the base end of which is pivotally secured to the valve housing;
an arm driving device for moving a tip end of the pivot arm between a first position where the valve disk is in the completely opened position and a second position where the valve disk is in the completely closed position; and
a power transmission device for transmitting the movement of the pivot arm to the valve disk;
the power transmission device having a pair of holders facing each other with a space therebetween, mounted on a back surface of the valve disk opposite to the valve seat, a first roller guide groove formed on each of opposite surfaces of the holders, a valve disk support fixed to the tip end of the pivot arm, movable relative to the valve disk, a second roller guide groove formed on the valve disk support so as to face to the first roller guide groove, a third roller guide groove formed on the valve disk support, a supporting plate, a fourth roller guide groove formed on the supporting plate so as to face to the third roller guide groove, a first roller engaging with the first and second roller guide grooves, and a second roller engaging with the third and fourth roller guide grooves, each of the first and second roller guide grooves extending downwards obliquely so as to be separated from the valve disk, and each of the third and fourth roller guide grooves extending downwards obliquely so as to approach to the valve disk.
A pendulum gate valve of the present invention comprises a valve housing including an interior space and first and second openings opposite to each other;
a valve seat disposed in the interior space around the edge of the first opening;
a valve disk mounted relative to the valve housing so that the valve disk is movable within the interior space between a completely opened position and a completely closed position, the valve disk being constructed so that when the valve disk is moved to the closed position the valve disk engages the valve seat and seals the first opening;
a pivot arm, the base end of which is pivotally secured to the valve housing;
an arm driving device for moving a tip end of the pivot arm between a first position where the valve disk is in the completely opened position and a second position where the valve disk is in the completely closed position; and
a power transmission device for transmitting the movement of the pivot arm to the valve disk;
the power transmission device having a pair of holders facing each other with a space therebetween, mounted on a back surface of the valve disk opposite to the valve seat, a first roller guide groove formed on each of opposite surfaces of the holders, a valve disk support fixed to the tip end of the pivot arm, movable relative to the valve disk, a second roller guide groove formed on the valve disk support so as to face to the first roller guide groove, a third roller guide groove formed on the valve disk support, a supporting plate, a fourth roller guide groove formed on the supporting plate so as to face to the third roller guide groove, a first roller engaging with the first and second roller guide grooves, and a second roller engaging with the third and fourth roller guide grooves, the first roller guide groove extending downwards obliquely so as to be separated from the valve disk and then extending downwards substantially vertically, the second roller guide groove extending downwards obliquely so as to approach to the valve disk and then extending downwards substantially vertically, the third roller guide groove extending downwards obliquely so as to approach to the valve disk and then extended downwards substantially vertically, and the fourth roller guide groove extending upwards obliquely so as to be separated from the valve disk and then extended upwards substantially vertically.
The pendulum gate valve has a member for preventing the supporting plate from moving relative to the valve disk in the moving direction of the pivot arm.
The pendulum gate valve has a member for preventing resiliently the supporting plate from moving relative to the valve disk in the moving direction of the pivot arm.
The pendulum gate valve has a member for preventing resiliently the valve disk from moving relative to the valve disk support in the moving direction of the pivot arm.
The pendulum gate valve has a member for preventing resiliently the valve disk from moving relative to the valve disk support in the moving direction of the pivot arm.
The pendulum gate valve has a stopper projected downwards from the lower end of the valve disk.
Other objects and advantages will become apparent from the following description of the preferred embodiments taken in conjunction with the accompanying drawings.